Dual backset deadbolt assembly

Abstract

A dual backset deadbolt assembly to be associated with a lock having a rotatable cylinder which has two axially extending crank members for actuating a deadbolt to move in two opposite directions, wherein the deadbolt assembly comprises a deadbolt housing holding a deadbolt, a rear extension housing having two side plates with aligned crank holes therein, a transmission plate having a front end engaging with the deadbolt, and two independently movable axial strip members slideably provided between two side plates on either side of the crank holes provided in the side plates, the strip members being connected to the rear forked portion of the transmission plate and having a plurality of teeth each extending into each crank hole, the strip members being selectable for cooperation with the operative crank member by the engagement of one of the teeth and the operative crank member.

What I claim is: 
     
       1. A dual backseat deadbolt assembly to be used in association with a lock having a rotatable cylinder which has two axially extending crank members for actuating said deadbolt assembly to move in either one of two opposite directions, wherein said deadbolt assembly comprises: a deadbolt housing;   a deadbolt mounted in said deadbolt housing for moving to a locking position or an unlocking position upon rotation of said lock;   an extension housing having two parallel side plates which have front ends connected to said deadbolt housing, each one of said side plates having a plurality of crank holes, said plurality of crank holes of one side plate being respectively aligned with said plurality of crank holes of the other side plate to form through-holes, each one of said through-holes establishing a different selectable backset distance of said deadbolt and being capable of receiving said crank members so that said crank members can be turned about a horizontal axis at one of said backset distances;   a transmission plate means slideably provided between said side plates, said transmission plate means having a front engaging member and a rear forked portion, said front engaging member extending into said deadbolt housing and engaging with said deadbolt;   two independently movable axial strip members slideably provided between said side plates, one of said axial strip members being above said through-holes and the other said axial strip member being below said through-holes, each one of said axial strip members being connected to said rear forked portion of said transmission plate means and having a plurality of teeth extending into said through-holes, each one of said plurality of teeth being capable of engaging with one of said crank members when said lock is rotated, wherein rotation of said lock causes one of said crank members to cooperatively engage a tooth on one of said axial strip members, said axial strip members being selectable for cooperation with one of said crank members depending on which direction said lock is rotated.   
     
     
       2. A dual backset deadbolt assembly as claimed in claim 1, wherein said side plates have two crank holes to form two through-holes. 
     
     
       3. A dual backset deadbolt assembly as claimed in claim 2, wherein said rear forked portion of said transmission plate means has two rearwardly extending prongs, each one of said prongs having a hook member to engage with each one of said axial strip members. 
     
     
       4. A dual backset deadbolt assembly as claimed in claim 3, wherein said axial strip members include two linear strip members, one linear strip member being positioned above said through-holes and the other linear strip member being positioned below said through-holes, each one of said linear strip members having a front engaging member to engage with said hook member of each of said prongs and having two spaced apart teeth extending respectively into said through-holes. 
     
     
       5. A dual backset deadbolt assembly as claimed in claim 3, wherein said axial strip members include two strip members each one of which has two limbs extending respectively above and below said through-holes, each one of said limbs having a tooth, said tooth on one of said limbs being staggered with respect to said tooth on the other one of said limbs so that said teeth extend into respective through-holes, said two strip members being abutted with one another and having engaging members extending into the housing. 
     
     
       6. A dual backset deadbolt assembly as claimed in claim 3, wherein said transmission plate means is formed integrally with said axial strip members, said transmission plate means including two transmission plates which are abutted with one another, said axial strip members being formed from said transmission plates having two of said prongs extending therefrom, each of said transmission plates having two teeth, said teeth on one of said transmission plates being staggered with respect to said teeth on the other one of said transmission plates and all of said teeth extending into respective through-holes. 
     
     
       7. A combination of a cylinder lock and a dual backset deadbolt assembly comprising: a deadbolt housing;   a deadbolt mounted in said deadbolt housing for moving to a locking position or an unlocking position upon rotation of said lock;   a cylinder lock having a rotatable cylinder which has two axially extending crank members for actuating said deadbolt to move in either one of two opposite directions;   an extension housing having two parallel side plates which have front ends connected to said deadbolt housing, each one of said side plates having a plurality of crank holes, said plurality of crank holes of one side plate being respectively aligned with said plurality of crank holes of the other side plate to form through-holes, each one of said through-holes establishing a different selectable backset distance of said deadbolt and being capable of receiving said crank members so that said crank members can be turned about a horizontal axis at one of said backset distances;   a transmission plate means slideably provided between said side plates, said transmission plate means having a front engaging member and a rear forked portion, said front engaging member extending into said deadbolt housing and engaging with said deadbolt;   two independently movable axial strip members slideably provided between said side plates, one of said axial strip members being above said through-holes and the other said axial strip member being below said through-holes, each one of said axial strip members being connected to said rear forked portion of said transmission plate means and having a plurality of teeth extending into said through-holes, each one of said plurality of teeth being capable of engaging with one of said crank members when said cylinder lock is rotated, wherein rotation of said cylinder lock causes one of said crank members to cooperatively engage a tooth on one of said axial strip members, said axial strip members being selectable for cooperation with one of said crank members depending on which direction said lock is rotated.   
     
     
       8. A combination as claimed in claim 7, wherein said crank members of said cylinder lock having a concave cross-section substantially similar to a segment of an annulus, the configurations of said crank members being symmetrical with respect to an axis of rotation of said rotatable cylinder.